Approval has been secured to build a £139 million police college near Cookstown.
The 250-acre site, which will be in use from 2015, will also be used to train prison officers and firefighters.
The Department of Finance and Personnel passed the business case for Desertcreat at the end of last week.
A full planning application will be lodged within six months and a tendering process launched.
Work is due to start in 2013.
The project was first announced in 2004 and was originally due to be finished in 2008. The cost envisaged at the time was £80 million.
Justice Minister David Ford said: "This is an important milestone for everyone associated with the Desertcreat project and one which brings closer the building of an integrated public services training college with world-class facilities."